ISLAMABAD, Pakistan, June 28 -- More than 70 years ago, the British army went to war against tribal forces loyal to a charismatic religious figure in what is now the Pakistani region of Waziristan. The ensuing guerrilla conflict lasted more than a decade. The British troops, though far more numerous and better armed, never captured the renegade leader and finally withdrew from the region.

Today, the Pakistani army is preparing to launch a major operation against another warrior in Waziristan, the ruthless Islamist commander Baitullah Mehsud. Taking a lesson from history and its own recent failures, the army is attempting to isolate and weaken Mehsud before sending its troops into battle.

Every day for the past two weeks, Pakistani bombers have crisscrossed Mehsud's territory, pounding his suspected hideouts and killing dozens of his fighters, including 16 who officials said died in bombing raids Saturday. Military forces have also surrounded the region to choke off Mehsud's access to weapons and fuel from outside.

"We are trying to shape the environment before we move in for the fight," Maj. Gen. Athar Abbas, the chief military spokesman, said in an interview. "We are also trying to minimize the loss of life. Ours is the only institution that can stand up to the militants, but public support is crucial. When we do move in, it must only be against Baitullah and his group. We cannot afford to provoke a tribal uprising."

So far, the effort has produced mixed results. On Tuesday, a Mehsud loyalist assassinated a key pro-government tribal leader in South Waziristan, and U.S. drone strikes killed 46 people at the funeral of a slain Mehsud commander, muddying the waters of tribal loyalties and antipathies.

"It is now clear that any tribals who side with the army will be violently suppressed," said Rifaat Hussain, a professor of defense studies at Quaid-i-Azam University here. "They may tacitly support the state, but they will not dare actively support it." He also noted that many army officers are from the same ethnic Pashtun group as Mehsud, making them reluctant to take him on.

As the days pass without the launch of a full-scale operation, experts said Mehsud -- who army officials estimate commands about 10,000 tribal fighters -- has had the time to gather support from sympathizers in other areas of Pakistan and abroad.

Since April, the army has enjoyed unprecedented public backing for a series of anti-militant operations, because of a mixture of high-profile terrorist bombings and revelations of cruel excesses by Taliban forces in the northwestern Swat Valley. But lately, some Pakistani commentators have cast doubt on the wisdom of taking on Mehsud's fanatical hordes.

"The decision to launch a military operation in this highly sensitive border region is ill-conceived, ill-advised, ill-timed," Roedad Khan, a retired government official, wrote Friday in The News International newspaper. Khan recalled the 1930s operation in which 40,000 British and Indian forces failed to crush Mirza Ali Khan, known as the Fakir of Ipi, a religious and tribal leader in North Waziristan. The retired official warned that by attacking next-door South Waziristan, the army could open a "massive, self-inflicted wound."

Sources close to the armed forces said there were concerns that the military was being pushed into the new campaign by Pakistan and U.S. officials too soon after taking on thousands of Taliban fighters in Swat. The operation there sent more than 2 million people fleeing and used up military resources.

The sources, who spoke on the condition of anonymity because of diplomatic sensitivity, said there was also concern in the military that the continuing U.S. drone attacks were doing more harm than good, killing a few important militant figures but stoking anti-American sentiment throughout the tribal region.

"The drone attacks have a short-term positive impact, but their long-term effect is to create public hostility," one military source said. "People see them as a breach of sovereignty and think the state is leaving its own citizens at their mercy."

Abbas said he could not comment on the drone issue, and he would not say how soon the ground operation in Waziristan would begin. However, he said that although the army was prepared to go after Mehsud and the fighters, "we are dealing with a lot of complexities and constraints. We can only go so far without hurting our long-term interests."

Abbas acknowledged that the government had decided to withdraw the army from South Waziristan in January after a brief effort to attack Mehsud, but he said the military was in a far better political position today to go after the militants, because it enjoys strong public support while Mehsud, once seen as a Robin Hood figure by many Pakistanis, has become a ruthless criminal in the public's eye.

Abbas also took issue with observers who suggest that South Waziristan is going to be a far tougher fight than Swat. He said Swat was an "ideal territory for guerrilla fighters" because it is mountainous, forested and heavily populated. In contrast, he said, South Waziristan is barren and sparsely populated, with few places for insurgents to hide.

Still, Abbas said that even if Mehsud is captured or killed and his movement crushed, the problems that spawned it will not vanish overnight. "The tribal areas have been neglected for 50 years," the spokesman said. "We will do our part, but there has to be follow-up by the civilian administration, better governance, more development. This is going to be a long haul."